Many portable communication devices, such as two-way radios, are utilized to perform different types of communication. These types of communication, which may occur simultaneously in parallel, include standing wave radio transmission, land mobile radio (LMR) transmission, long-term evolution (LTE) transmission, and audible alert tone transmission. Portable communication devices may be battery-powered and may include multiple components, including a transceiver and a processor. Each component of the portable communication device may draw power or current to operate, but the device may be restricted in power consumption or current consumption to satisfy compliance with one or more standards, including Appareils destinés à être utilisés en ATmosphères EXplosibles (ATEX), Underwriters Laboratories (UL), and International Electrotechnical Commission System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres (IECEx).
For example, Division 1 compliance with UL standards may require a communication device to operate regularly in environments with concentrated levels of flammable or combustible material and limit peak instantaneous current draw of the device to maintain safety and security. Peak instantaneous current may be drawn in a variety of scenarios in such environments. For example, safety and security may be maintained by communication signal(s) that rely on audible alert tones. Present portable communication devices do not enable alert tones to be produced at desirable levels to maintain safety and security without exceeding the power consumption or current consumption requirements imposed by such standards. However, there are situations in which it may not be feasible for the alert tone volume or the perceived loudness of an alert tone to be reduced to satisfy power consumption limits or current consumption limits. For example, in a situation in which a user is operating in an environment with concentrated levels of flammable or combustible material, such as one defined by Division 1 UL standards, reductions of alert tone volume or perceived loudness may inhibit proper use of the portable communication device to maintain safety and security. Moreover, some portable communication devices may achieve a reduction in power consumption or current consumption by relying on techniques that may not satisfy the requirements of other portions of the same standard or other compliance standards.
There exists a limitation with respect to limiting the power consumption or current consumption without violating other requirements associated with a compliance standard. This functionality typically may not be achieved by simply reducing the alert tone volume or adding an intermediate energy storage device, such as a capacitor, to boost the alert tone output.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The system, method, and apparatus components have been represented where appropriate by suitable symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.